The velocity of sound is one of the important acoustic parameters in ocean. For realizing rapid and high-precision measurements of seawater sound velocity, a sound velocity measurement method whose system architecture is simple was adopted.The measurements of sound propagation time and velocity value were achieved by continuous wave signal’s parameter estimation method. A pseudo-random sequence was introduced to modulate and handle continuous waves, which overcame the cycle ambiguities and echo interference problems of single-frequency signal in measurement. A sound velocity measurement platform was built to conduct system calibration and measurement experiment. Experiment results show that this method has high accuracy and fast response and is suitable for ocean sound velocity profile measurement on subaqueous mobile platform.